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D. S. MCAFEE.

4TREATING FINE GRES.

APPLICATION min Aue.x6.191s.

Patented June 3, 1919.

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citizen of the United States, residin at` N ew York city, in the county of New nANInL smnnns Mearnn, or NNW YORK, N. Y., ASSIGNOR ro THE Donn. COMPANY,

l A CORPORATION or Imnexwaltr.l

TREATING FINE ORES.

To all whom t may concern:

Be it known that l, DANIEL S. MCAFEE, a

ork State of New York, have invented certain new and useful Improvements in Treating Fine Orcs; and l do-hereby declare the following to be a full, clear, and exact description of the invention, such Ias'will enable others skilled 'rin the art to which it appertains to make and u-se the Same.

The present invention relates to the treatment o 'Ore sludges and slimes such as' Jthe slimes of ore leaching operations, blast furnsaoe sludges, and the like, encountered in metallurgical Operations wherein fine ores are to .be sintered. Thus for instance,

the ordinary treatmentof iron, pyrite the ,Ore fis first burned to remove the greater part of the sulfur, after which the ore is leached to remove the copper; the leaching operation being carried out first in a classifier which separates out the sands, and then in 1 settling tanks or thickeners in which the slimes are separated from the leaching liquor, which then passes toa cementation plant where the copper is precipitated. The sands resulting from the leaching operation arecommonly conveyed to a sintering plant Where the sulfur is almost entirely removed and the iron ore is agglomerated sufficiently to be treated in a blast furnace. The slimes resulting from the thickening operation are Y commonly of such a character, due to their stilckiness and abrasive and corrosive proper- "ties that their subsequentjtreatment is very f diiicult. The heavy sticky slime, even when mixed with the sand from the classifiers', is very diliicult to handle on a belt conveyor,

even with the provision of Scrapers, brushers or pounders for cleaning the belt. The mix-i in of the slime with the sand is extremely di cult; the mixture'carriesjso much molsture that there is considerable `drip from the conveyer, and lon account of ,the abrasive action of the. slime ordinary conveying apparatus is rapidly destroyed. rMany expedi-` ents have been proposedto overcome these diculties, but without success. It has also been vproposed tol filter the slime, but this method is objectionable owing to its high first cost and its heavy 11p-keep costs, besides Specication Of Letters Patent.

lcent. to three-tenths of a per cent.

Patented June 3, 15H9.

Application filed laugust 16, 1 918. Serial No. 250,126.

requiring a plant ofl considerable complication.

It is an object of the present invention to provide a method of treating the slime in such a way that it can be handled by simple apparatus advantageously and economically Y `cooperating with the sintering apparatus commonly` usedin such installations.

ln accordance with the preferred practice of the present invention, the slime or sludge is pumped to a bin into which the hot returns from a sintering machine are discharged; rst being diluted if it has previ- Iously been dewaitered to such 4an extent as l to prevent ready pumping thereof. The dilute slime or sludge from the pump is sprayed over the hotv returns, where the `Water is quickly evapora-ted, and the dry slime or sludge adheres to, or becomes mixed with, the returns which may be thensent through the sintering machine to be agglom- 'erated before ybeing fed to a blast furnace or otherwise utilized. Y

vThe details of the invention will appear more clearly from a description of the process `and apparatus by which it is carried out.

ln` connection with this description, reference should be made to the accompanying fiow sheet in which the apparatus used for treating 'the various materials, and the course of the materials through the plant is diagrammatically illustrated, and indicated by f appropriate legends.

As an example of the practice of the invention, and to enable .those skilled in the art to understand it, the invention is hereinafterI described as applied to a plant treating iron pyrite.

As the ore comes from the S()2 burners, it carries a smjall percentage of sulfur, for instance, -about two per-cent., and the copper content varies from two and one half per From the storage bin, the ore is conveyed to the classifiers where i-t is sepa-rated into sands and fines. The sands are lea'ched and then conveyed to ore bins for subsequent treatment in :a sintering machine which may conveniently be of the Dwight Lloyd type. If

yfine iron-bearing oxid material is being treated, fuel Imust be mixed with the ore, y

because the latter contains no heat furnishing constituent. This fuel may be coke supplied in proper amount from a bin locatedto be conveyed to the blast furnaces, while the under-size--insuficiently agglomerated for blast furnace use-is partially quenched With water and then dumped into the return sinter bin,.to be fed again onto the sintering machine.

The fines from the classifiers are conveyed through thickeners from whichr the copper solution is drawn oif and carried to a cementation plant for obtaining copper precipitation. The slime from the thickener is conveyed by means of a diaphragm pump to a sump tank where it is diluted with water to preferably about 50% moisture. A centrifugal pump conveys the slime from the sump tank to a box set above the return sinter bin and having a perforated bottom, so that the slime falls upon the hot returns as a shower, causing the Water to be quickly evaporated and the ne particles of the dried slime to adhere to or be mixed with turn sinter bin, the returns with their coatings of dried slime may be conveyed to the sintering machine to be agglomerated for subsequent treatment in the blast furnace. Various mechanical expedients may be adopted for handling conveniently the slime taken from the sump tank, such as the provision of long sweeps in the discharge line from the centrifugal pump, and the provision of a vhard lead pump and pipe. In order to avoid, as far as possible, the cutting action of the slime on the gland of the pump, the water supplied to the slime to dilute it may be introduced at the pump gland to protect the packing. A further expedient of adding all fresh water as a spray at the sand end of the last classifier will be found of advantage, as it will remove all slime from the sand and lessen the acid and copper loss at this point.

It will be understood that the above de.- scribed preferred procedure is to be taken merely as illustrative of the substantial character of the invention and that it may be modified and rearranged in many ways. Thus it will be understood that the slime or sludge may be added to the hot product of or on the sintering machine in many ways and at any desirable point. Particularly vit may be desirable, in many cases, to use dilute slime or sludge for quenching the returns at the grizzly. c

It will be understood that the invention is not limited to the treatment of slime resulting from the leaching of iron pyrite as indicated diagramniatically on the flow sheet.

I claim:

1. The herein described process of treating slimes orsludges encountered in metallurgical operations wherein line ores are to be sintered which consists in adding the slimes to the hot product of a sintering machine to simultaneously dry the slimes and quench the said product.

` 2. The herein described process of treating slimes or sludges encountered in metallurgical operations wherein fine ores are to be sintered which consists in adding the slimes to the hot returns of a sintering machine to simultaneously dry the slimes and quench the returns.

3. The'herein described process of treating slimes or sludges encountered in metallurgical operations wherein fine ores are to be s intered which consists in adding the slimes to the hot returns of a sintering machine and then passing the returns coated with slime through the sintering machine to agglomerate them.

4. The herein described process of treating slimes or sludges encountered in metallurgical operations wherein fine ores are to bev sintered which consists in diluting the slimes, and conveying the dilute slimes through a pump line 2 and spreading them upon the hot product of a sintering machine to simultaneously dry the slimes and quench the said product.

5. The herein described process of treating fine lores which consists in separatingy the ores into sands and slimes, treating the sands in a sinteringmachine to agglomerate them, and adding the slimes to the hot product of the sintering machine to simultaneously dry the slimes and quench the said product.

6. The herein 'described process of treating fine ores which consists in separating the -ores into sands and slimes, treating the sands in a sintering-machine to agglomerate them, adding the slimes to the hot returns from the sintering machine and treating the mixed returns and slimes in the sintering machine to agglomerate them.

7. The herein described process of treatingne ores which consistsin separating the ores into sands and slimes, diluting the slimes, treating the sands in a sintering machine to agglomerate them,- and conveying the dilute slimes vthrough a pipe line 2 and spreading them upon the hot product of a sintering machine to simultaneously dry the slimes and quench the said product.

spreading them upon the hot returns of a4 sintering machine to simultaneously dry the slimes and quench the said returns, and treating the mixed returns and sliines in the 10 sintering machine to agglomerate them.

In testimony whereof I aiiX my signature.

DANIEL SHIELDS MGAFEE. 

